A conventional solar cell structure with a p-type base has a negative electrode that is typically on the front-side or sun side of the cell and a positive electrode on the backside. It is well-known that radiation of an appropriate wavelength falling on a p-n junction of a semiconductor body serves as a source of external energy to generate hole-electron pairs in that body. Because of the potential difference which exists at a p-n junction, holes and electrons move across the junction in opposite directions and thereby give rise to flow of an electric current that is capable of delivering power to an external circuit. Most solar cells are in the form of a silicon wafer that has been metalized, i.e., provided with metal contacts that are electrically conductive.
Electrode of solar cell is usually formed by applying a conductive paste onto a substrate and firing it. Conductive paste is applied onto the surface of solar cell and the paste is fired for sintering. Paste typically contains (a) conductive power such as silver or aluminum, (b) glass frit as inorganic binder, (c) organic medium and (d) optional additive.
U.S. Pat. No. 7,494,607 discloses conventional organic mediums including ethylhydroxyethyl cellulose, wood rosin, mixtures of ethyl cellulose and phenolic resins, polymethacrylates of lower alcohols, monobutyl ether of ethylene glycol monoacetate ester alcohols and terpenes such as alpha- or beta-terpineol or mixtures thereof with other solvents such as kerosene, dibutylphthalate, butyl carbitol, butyl carbitol acetate, hexylene glycol and high boiling alcohols and alcohol esters.
Although various methods and compositions for forming solar cells exist, there is a need for compositions, structures, and devices which have improved electrical performance, adhesion properties, and methods of making.